'Fast' in the Bible

And the LORD said unto Satan, Hast thou considered my servant Job, that there is none like him in the earth, a perfect and an upright man, one that feareth God, and escheweth evil? and still he holdeth fast his integrity, although thou movedst me against him, to destroy him without cause.

He shall lean upon his house, but it shall not stand: he shall hold it fast, but it shall not endure.

My righteousness I hold fast, and will not let it go: my heart shall not reproach me so long as I live.

When the dust groweth into hardness, and the clods cleave fast together?